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Retracted: tert‐ Butyl Hydroperoxide and Tetrabutylammonium Iodide‐ Promoted Free Radical Cyclization of α‐Azido‐ N ‐arylamides
Author(s) -
Li Dianjun,
Yang Tonghao,
Su Hailin,
Yu Wei
Publication year - 2014
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201400420
Subject(s) - chemistry , radical , oxidizing agent , tert butyl hydroperoxide , deprotonation , medicinal chemistry , yield (engineering) , intramolecular force , imine , iodide , photochemistry , oxygen , radical cyclization , benzene , organic chemistry , catalysis , ion , materials science , metallurgy
The oxidizing system of tert ‐butyl hydroperoxide (TBHP) and tetrabutylammonium iodide (TBAI) is capable of engendering α‐(aminocarbonyl)iminyl radicals from α‐azido‐ N ‐phenylacetamides. These iminyl radicals preferably undergo intramolecular attack on the benzene ring to give azaspirocyclohexadienyl radicals, which are readily captured by O 2 under an oxygen atmosphere to yield azaspirocyclohexadienones. In the absence of oxygen, the reaction will afford quinoxalin‐2‐one products. The generation of α‐(aminocarbonyl)iminyl radicals is proposed to involve an initial deprotonation and denitrogenation, and subsequent oxidation of thus formed imine intermediates by tert ‐butoxy radical and/or tert ‐butyl peroxyl radical.